Planning Permission in Hounslow
London Borough in London · Last updated April 2026
Hounslow stretches from the Thames-side communities of Chiswick, Strand on the Green, and Isleworth through to Feltham, Hanworth, and Cranford in the west. The borough contains some of London's finest heritage properties — Chiswick House (Grade I), Syon House, Osterley Park, and Boston Manor — alongside major economic assets including the Great West Corridor Opportunity Area and proximity to Heathrow Airport. With 29 conservation areas, over 500 listed buildings, and significant Green Belt and Metropolitan Open Land (~36% of the borough), planning in Hounslow requires careful navigation of heritage and environmental constraints.
The borough's planning framework is governed by the Hounslow Local Plan 2015 (adopted September 2015), with a comprehensive replacement plan (2020-2041) currently at examination stage following submission in June 2025. The council has also adopted a Character, Sustainability and Design Codes SPD (2024) which is the primary design reference for householder applications. Three Article 4 directions provide additional controls on HMO conversions (borough-wide), commercial-to-residential changes (in employment areas), and external alterations in Bedford Park and Gunnersbury Park conservation areas.
With an approval rate of just 66.2% — significantly below the national average of 86.9% — Hounslow is one of the more cautious planning authorities in London. This makes pre-application advice particularly valuable to understand the council's expectations before investing in detailed drawings. Whether you're in a riverside conservation area or a suburban street near Heathrow's flight paths, checking your property's constraints early can save time and money.
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What can I build in Hounslow?
| Project type | Likely permitted development | May need planning permission | Likely needs planning permission |
|---|---|---|---|
| Rear extension (single storey) | Only outside conservation areas and Article 4 zones | Properties near boundaries or Green Belt fringe areas | Conservation areas (29), Article 4 zones (3), listed buildings |
| Rear extension (two storey) | Only outside conservation and Article 4 areas | Check distance to boundary ≥7m or Green Belt fringe areas | Conservation areas (29), Article 4 zones (3), listed buildings |
| Side extension | Detached houses outside protected zones | Semi-detached properties (half-width rule) | Conservation areas (29), Article 4 zones (3), listed buildings |
| Loft conversion (dormer) | Only outside conservation and Article 4 areas | Properties on prominent corners or in Article 4 areas (Bedford Park and Gunnersbury Park conservation areas, Houses in Multiple Occupation (borough-wide)) | Conservation areas (e.g. Feltham Town Centre, Cranford Village, Hounslow Cavalry Barracks), listed buildings, flats |
| Loft conversion (Velux/rooflight) | Most of Hounslow outside conservation areas | Front-facing rooflights in conservation areas | Listed buildings, Article 4 areas |
| Outbuilding / garden office | Only outside conservation areas and Article 4 zones, if within size/height limits | Large outbuildings covering >50% of garden | Conservation areas (side or front), listed buildings, Green Belt |
| Porch | Most properties if within 3m² and 3m height | Properties in Article 4 areas or near highway boundary | Conservation areas with restrictions, listed buildings |
| Solar panels | Most properties (roof-mounted) | Panels protruding beyond roofline | Listed buildings, conservation areas (if visible from road) |
| Driveway / hard standing | If using permeable surfacing | Non-permeable surfacing over 5m² | Conservation areas with specific restrictions |
| Garage conversion | Most of Hounslow (internal works) | If changing external appearance significantly | Listed buildings |
This is general guidance based on Hounslow's planning constraints. Your specific property may differ — use our free PD checker to get a result tailored to your address.
Permitted development in Hounslow
Permitted development rights in Hounslow follow national rules but are modified by 3 Article 4 directions and 29 conservation areas. The borough-wide HMO direction (September 2023) requires planning permission for all conversions to houses in multiple occupation. A 2025 direction removes Class MA (commercial-to-residential) and Classes ZA, AA, AB (new dwellings) PD rights in town centres, neighbourhood centres, industrial locations, and key employment sites. In Bedford Park and Gunnersbury Park conservation areas, an additional Article 4 direction removes PD rights for windows, doors, roofing, and boundary treatments — providing protection beyond the standard conservation area restrictions. Standard householder PD rights for rear extensions, loft conversions, and outbuildings apply outside these constraints, but the council's Character, Sustainability and Design Codes SPD (2024) sets high design expectations that should inform any scheme.
What Hounslow expects from your project
Hounslow's design expectations are set by the Character, Sustainability and Design Codes SPD (adopted 2024), which replaced three earlier documents including the Residential Extension Guidelines. The SPD provides detailed guidance on extensions, materials, fenestration, and landscaping appropriate to each character area. The borough's extraordinary heritage properties — including 23 Grade I listed buildings such as Chiswick House, Syon House, Osterley House, and Boston Manor House — set a high bar for design quality in surrounding areas. Properties near Heathrow may need to incorporate noise insulation measures, and the council's Climate Change Mitigation and Adaptation SPD (2025) introduces zero-carbon building requirements. The Air Quality SPD is relevant for properties near major roads and the airport, where additional mitigation may be needed.
Local design guidance
Character, Sustainability and Design Codes SPD
Adopted 2024Local Plan: Hounslow Local Plan
The Hounslow Local Plan was adopted in September 2015. The plan addresses development pressures from Heathrow Airport, the Golden Mile at Brentford and significant riverside development opportunities. The London Plan (2021) also applies.
Emerging / replacement plan
Hounslow is preparing a new Local Plan. A Regulation 18 consultation ran in 2022-2023, and a Regulation 19 Pre-Submission consultation ran in 2024.
29 conservation areas
Hounslow has a high number of conservation areas. Check whether your property falls within one before starting any work — conservation area status significantly restricts what you can do without planning permission.
66.2% approval rate
Hounslow's planning approval rate is below the national average of 86.9%. If your project needs planning permission, consider pre-application advice before submitting — it significantly reduces refusal risk.
Conservation areas in Hounslow
29 designated conservation areas
Hounslow's 29 conservation areas protect a remarkable diversity of heritage settings. The Thames-side areas — Strand on the Green (1968), Old Chiswick (1969), and Isleworth Riverside (1972) — preserve historic waterfront character with Georgian and earlier buildings. Bedford Park (1970) is internationally recognised as the world's first planned garden suburb (from 1875) and has an Article 4 direction for additional protection. Chiswick House conservation area protects the setting of the Grade I Palladian villa and its gardens. The Grand Union Canal and Boston Manor area preserves the industrial waterway corridor. The newest designations are Chiswick High Road (2015) and Glebe Estate (2024). The Kew Gardens UNESCO World Heritage Site buffer zone extends into the borough, affecting development near Kew Bridge. Within any conservation area, permitted development rights are restricted for cladding, side extensions, roof additions, satellite dishes, and chimney alterations.
Article 4 directions in Hounslow
3 Article 4 direction areas
Listed buildings in Hounslow
There are 514 listed buildings in Hounslow. If your property is listed, permitted development rights are significantly restricted. Most external and many internal alterations will require listed building consent, which is separate from planning permission. Always check with Hounslow's conservation team before starting any work on a listed property.
Planning application statistics
Year ending September 2025 | Source: MHCLG planning application statistics
Hounslow received 1,485 planning applications and decided 1,357 in the year ending September 2025. The approval rate of 66.2% is below the national average of 86.9%. Major applications are expected to be decided within 13 weeks, while householder and other non-major applications have an 8-week target. The “in time” figures include decisions made within agreed extensions of time.
Hounslow processes approximately 1,485 planning applications per year, with an approval rate of 66.2% — one of the lowest in London and well below the 86.9% national average. This cautious approach makes pre-application engagement essential. The council achieves 93.8% of householder decisions within the 8-week target and 92.6% of major decisions on time. The delegation rate is 98.4%, with virtually all decisions made by planning officers. The borough's Housing Delivery Test score of 108% (2023 measurement) means no additional constraints apply, though forecasts suggest this may fall significantly in future measurements. Major regeneration is concentrated at the Great West Corridor Opportunity Area (targeting 7,500+ new homes and 14,000 jobs), with Brentford Town Centre undergoing transformation through multiple development sites. The emerging Local Plan (2020-2041) is currently at examination and may be adopted in 2026.
If your project complies with permitted development rules, you don't need to worry about approval rates — a Lawful Development Certificate is a factual assessment, not a judgment call.
Recent planning applications in Hounslow
Browse what's been approved near you
Seeing what similar projects have been approved near your property can help you understand what Hounslow expects in terms of scale, materials, and design. It's also useful for gauging how quickly the council processes applications.
Search planning applications on Hounslow's portal →Data from MHCLG planning application register. Search for householder applications (H01/H02) to see extensions and loft conversions in your area.
Housing delivery in Hounslow
Housing Delivery Test 2023 measurement | Source: MHCLG
Hounslow delivered 4,694 homes against a requirement of 4,330 over the three-year measurement period, giving a Housing Delivery Test score of 108%. This is above the 95% threshold, which means there are no government-imposed consequences for housing under-delivery. Planning applications in Hounslow are assessed on their own merits under standard planning policies.
Lawful Development Certificates in Hounslow
A Lawful Development Certificate (LDC) is formal confirmation from Hounslow that your project is lawful under permitted development rules. It is not legally required before you build, but it is the only official document that proves your project did not need planning permission. Most solicitors will ask for one when you come to sell, remortgage, or insure your property.
Hounslow decided 818 householder applications in the year ending september 2025. Their 8-week performance of 93.8% is above the national average of 93%, which suggests LDC applications are likely to be processed on time. LDC applications follow the same 8-week statutory determination period as householder planning applications.
How to apply for an LDC in Hounslow
You can apply for a Lawful Development Certificate through the Planning Portal or directly through Hounslow's website. You will need to submit:
- A completed application form (available on the Planning Portal)
- A site location plan at 1:1250 or 1:2500 scale
- Existing and proposed floor plans and elevations
- A written description of the proposed works and how they comply with the GPDO 2015
- The application fee of £258
Hounslow must issue a decision within 8 weeks. If the application is approved, the certificate is a permanent legal record that the development is lawful. If refused, you can appeal to the Planning Inspectorate or amend your project and reapply.
Need help preparing your LDC application?
Our Permitted Development Certificate Report gives you a full PD eligibility assessment, property constraints check, and application checklist tailored to your address and project — so you can apply with confidence.
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Approval rates, decision patterns, Article 4 directions, fees & timelines, and council-specific tips for Hounslow.
Pre-application advice in Hounslow
Hounslow offers a pre-application advice service. The fee for householder pre-app advice is Fees vary by category — see council's 2025-26 fee schedule. Written advice, online meeting, and site visit options available.. You can typically expect a response within Varies by category.
Pre-app advice is worth paying for if your project is borderline, your property is in a conservation area, or your home is a listed building.
Think your project might be permitted development?
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Check your PD rights now →Submit pre-app requests to planningcomments@hounslow.gov.uk. Conservation team available on 020 8583 4941 for heritage queries.
Planning fees and timelines in Hounslow
| Application type | Fee | Typical timeline |
|---|---|---|
| Householder planning permission | £528 | Single dwelling — extension, loft conversion, outbuilding (April 2025 rate) |
| Lawful Development Certificate (proposed) | £264 | Confirm PD rights before starting work |
| Lawful Development Certificate (existing) | £298 | Retrospective — confirm existing work is lawful |
| Listed building consent | £0 | No fee — but application required for any works to listed building |
| Certificate of lawfulness (proposed use) | £264 | For proposed change of use |
| Prior approval (larger home extension) | £120 | Single-storey rear 4–8m (detached) or 3–6m (other) |
| Discharge of conditions | £145 | Per request (householder) |
| Non-material amendment | £44 | Minor changes to approved householder scheme |
Fees are set nationally and correct as of April 2026. Pre-application fees are set by Hounslow and may change. Building regulations fees are separate — see the building control section below.
Building regulations in Hounslow
Building regulations approval is separate from planning permission. Most extensions, loft conversions, and structural alterations need building regs approval even if they don't need planning permission.
Building control in Hounslow is provided by London Borough of Hounslow Building Control. You can also use a private approved inspector instead of the council's service.
Hounslow planning department
Your building project checklist for Hounslow
- Check if your property is in a conservation area — Hounslow has 29 conservation areas. Use our free checker or see the list above.
- Check for Article 4 directions at your address — Hounslow has 3 Article 4 areas. Check your address.
- Check if your property is listed — search the Historic England list.
- Use our free PD checker to see if your project qualifies as permitted development — Check now.
- Consider a Lawful Development Certificate if PD applies — it protects you when selling. Learn more about LDCs or get your PD Certificate Report.
- Consider pre-application advice if planning permission is needed — see the pre-application section above.
- Check building regulations — most extensions and loft conversions need building regs approval even if they don't need planning permission.
- Check Party Wall Act obligations if building near a boundary — read our Party Wall guide or use our free Party Wall tool.
- Notify your home insurer about planned building work.
- Get at least 3 quotes from builders and check their credentials.
Nearby planning authorities
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